How this estimate works
The calculator applies: 2 x (length + width) x height - openings. Keep measurements in one unit system and round up when suppliers sell whole units.
Limitations
Irregular walls, alcoves, gables, and curved surfaces need separate measurements.
Source to check
Read the authoritative guidance for wall area calculator
Frequently asked question
Should I include the ceiling? No. Measure and add the ceiling separately when it is part of the project.